picture angle, a law that, by the way, has not been accurately interpreted by the specialists 
for lenses with interior diaphragm. 
In order to complete this lens series | developed after the 60° and 90° lenses a super wide angle 
lens of 120° on the Aviogon basis and of similar power. The main problem put by such wide 
picture angles has been mentioned as | spoke of Russinov’s lens. One looks for a maximum of 
light in the picture corners. Extensive research work showed that it is possible to obtain a lu- 
minous flux 2.5 times more important than that given by the cosine law, the sharpness of the 
picture still being absolutely satisfactory. Such a lens is actually on trial (fig. 9). 
f AS 
b 
| 
NS d 
Fig. 9 
Super-Aviogon (1956) 
   
| would finally like to mention another important factor: survey lenses must have a residual 
distorsion of less than + 0.01 mm. | therefore have not carried on the elimination of distorsion 
as soon as it surely was below + 10 microns. Photogrammeters are absolutely right when the 
say that it is all the same to them if they have to compensate 20 or only 5 microns as such a 
residual distorsion can be reduced at the same costs to approx. +2 microns whereas there is no 
way to improve lateron a deficient sharpness or an imperfect brightness in the picture corners. 
Let me last but not least express my warmest thanks to prof. Kasper, manager of the photo- 
grammetric services of Messrs. Wild, for the extremely precious hints he gave me during the 
development of these new lenses. 
Printed in Switzerland 
picture edges as that indicated by Lambert's law of the cosine of the fourth power of the 
      
   
   
    
    
   
    
  
    
   
     
SI 
* VHi* C